Circuit breaker panelboard or load center



. D6026, 1957 H.J.HAMMERLY 3,360,690 I CIRCUIT BREAKER PANELBOARD OR LOAD CENTER Filed March 5, 1961 2 Sheets-Sheet 1 INVENTOR. HERMAN J. HAMMERLY A TTORNE Y Dec. 26, 1967 H. J. HAMMERLY' I 3,360,690

CIRCUIT BREAKER PANELBOARD OR LOAD CENTER Filed March 5, 1961 2 Sheets-Sheet 2 INVENTOR. HERMAN \J. HAMMERLY A 7 T RNEY United States Patent 3,360,690 CIRCUIT BREAKER PANELBOARD OR LOAD CENTER Herman J. Hammerly, Plainville, Conn, assignor to General Electric Company, a corporation of New York Filed Mar. 3, 1961, Ser. No. 93,109 2 Claims. (Cl. 317-119) ABSTRACT OF THE DISCLOSURE A circuit breaker panelboard, including a supporting pan having holes adjacent each of the mounting positions for the circuit breakers, the circuit breakers each having a depending tab which extends through a corresponding hole when the breaker is in mounted position; a locking rod underneath the support passes aligned holes in the depending tab portions to lock the breakers in place and prevent unauthorized changing of the circuit breakers.

This invention relates to a circuit breaker panelboard or load center and, more particularly, to locking means for preventing the unauthorized removal and replacement of selected circuit breakers from the panelboard without interfering with the removal and replacement of other circuit breakers.

In electric wiring installations, a number of circuit breakers for protecting a number of different respective circuits having widely varying ampere requirements are frequently mounted in a side by side relationship on the same circuit breaker panelboard. Since the ampere requirements of the circuits may vary over a wide range, it is necessary to also provide circuit breakers in a wide range of ratings, such as 15, 20, 30 and 50 amperes, in order to effectively protect the circuits. The selection of a proper circuit breaker for the protection of any particular circuit is, of course, dictated by the requirements of that circuit. The original selection and installation of circuit breakers is generally made at the time of wiring the circuits and is normally made by qualified workmen, thus practically assuring that a circuit breaker having a correct rating will be placed in each circuit. It is necessary that a correctly rated circuit breaker be placed in each circuit so that there will be no danger of fire. As added assurance that the initial installation will be correctly done, it is frequently the practice that such original installations are inspected and approved by proper civil authorities.

However, it sometimes occurs in practice that a circuit is substantially overloaded and, as a result, repeated opening or continual tripping of the associated circuit breaker is encountered. Such repeated opening of the circuit breaker may also occur occasionally because of a malfunctioning of the circuit breaker or because of other reasons. Because of such continuing nuisance tripping of the circuit breaker, a user may attempt to replace the correctly rated circuit breaker with one of a greater rating in order to stop the continual tripping, thus completely eliminating the protective effectiveness of the circuit breaker. It also occurs occasionally that a user may attempt to replace a faulty circuit breaker and may accidentally insert a breaker of a higher rating into the panelboard because of the similarity of the casings of circuit breakers having different ratings. Regardless of the reason for the insertion of a breaker having a greater than required rating, the insertion of such a breaker will defeat the protective function of the circuit breaker and thus create a danger of fire. Therefore, it is to be desired that replacement of circuit breakers with breakers having higher ratings by unauthorized personnel be discouraged, impeded, and effectively prevented by safety means which will prevent such unauthorized removal and replacement of circuit ICC breakers. It is also to be desired, however, that circuit breakers having low ratings be easily removable from the panelboard and be easily replaceable with replacement breakers having equally low ratings.

It is a principal object of this invention to provide means for use in a panelboard assembly containing circuit breakers of different ratings which will effectively prevent the removal and replacement of circuit breakers with breakers having higher ratings than the removed breaker by unauthorized personnel.

A further object of this invention is to provide locking means for use in a panelboard assembly which will effectively prevent the removal and replacement of selected circuit breakers by unauthorized personnel.

A still further object is to provide locking means for preventing the removal and replacement of circuit breakers by unauthorized personnel which may be used in combination with circuit breakers of the plug-in electrical type having conventional casings.

It is an additional object of this invention to provide a simple, inexpensive, and easy to manufacture locking means which may be removed from engagement with the circuit breakers by authorized personnel to allow for the removal and replacement of circuit breakers.

Briefly stated, in accordance with the illustrated embodiment of the invention, a panelboard support plate is provided on the front surface of which a plurality of circuit breakers having different ratings may be removably mounted. An aperture is provided in the support plate in conjunction with each of the circuit breakers mounted thereon. Tab retaining means, which may be secured to selected circuit breakers, extend through the apertures to the back surface of the support plate where a locking means engages the retaining tabs. The locking means, which is too large to pass through the apertures, contacts the back surface of the support plate, thus preventing the rtlernoval of the selected circuit breakers from the support p ate.

In accordance with the objects of the invention, the selected circuit breakers are, in practice, those having high ratings. While circuit breakers having low ratings may, under certain circumstances, be provided with the tab retaining means to prevent their removal by authorized personnel, they are not generally so provided, thus making possible their easy removal and replacement by ordinary workmen.

While the specifications concludes with claims particularly pointing out and distinctly claiming the subject matter of the invention, it is believed that the invention Will be better understood from the following description taken in connection with the accompanying drawings in which:

FIGURE 1 is a perspective view of a panelboard or load center assembly constructed in accordance with the invention, only one circuit breaker being shown in place;

FIGURE 2 is an end view of a panelboard assembly similar to that shown by FIGURE 1 showing two circuit breakers one of the breakers being in fully mounted position and the other being in partially mounted position; and

FIGURE 3 is an exploded view of a portion of the panelboard assembly of FIGURE 2.

Referring to the various figures, a panelboard is shown comprising an outer enclosure or box 9, a channel-shaped support plate 10 having a generally flat central support section 11 and two offset circuit breaker supporting flanges 12 and 13 disposed in a plane parallel to that of the support section 11. The plate 10 is removably mounted in the enclosure 9 by any suitable means (not shown). Arranged along the length of the front surface of each of the circuit breaker supporting flanges 12 and 13 in a spaced relation are a number of circuit breaker hook-shaped retaining elements such as the element 14, one retaining element being provided for each of the circuit breakers to be mounted on the supporting flanges. A slot or aperture 15 is provided in the support plate flanges 12 and 13, as particularly well shown by FIG- URE 3, on each side of the hook-shaped retaining elements 14. In addition, an eyelet 15a is formed adjacent the bend of each of the flanges 12 and 13 at each end of the support plate for a purpose to be described.

A number of relatively stationary line terminal contact blades 16 are provided for delivering power to the electric circuit breakers which are to be mounted on the support plate 10. The stationary contact blades 16 are electrically connected to bus bars 17 and 18 which are supported on suitable insulating supports such as, for example, insulating blocks 19 and 20. A power cable or wire is connected to each of the bus bars 17 and 18 by means of connectors 21 and 22, respectively.

The panelboard assembly is adapted to receive a number of electric circuit breakers such as the circuit breaker 25 shown in FIGURE 1. As best shown by FIGURE 2, each of the circuit breakers is provided at one end with a lug 30 which may be integral with the casing of the circuit breaker. The lug as on the circuit breaker casing is adapted to be received under one of the hook-shaped retaining elements 14. After engagement is made between the lug 30 and the retaining element 14 in the manner shown by circuit breaker 26 in FIGURE 2, the circuit breaker is rotated about the engagement into a fully mounted position in which a blade-receiving contact or socket (not shown) within the circuit breaker casing adjacent the other end thereof is moved into connected engagement with one of the contact blades 16 as shown by circuit breaker 27 in FIGURE 2.

In actual practice, a number of circuits having various ampere requirements may be wired into the same panelboard, thus making necessary the use of circuit breakers having various ratings in conjunction with the various circuits. In order to provide for maximum flexibility of the panelboard assembly, circuit breakers having different ratings should have identical casing structures so that a circuit breaker having any desired rating may be mounted in engagement with any selected retaining element 14 and the respective contact 16. Because of the identical casing structure of circuit breakers having different ratings, there is a possibility that, unless preventing means are provided, a workman or the user may replace a circuit breaker with another having a higher rating, thus completely destroying the protective function of the circuit breaker. Therefore, this invention provides locking means for preventing the removal and replacement of high rated circuit breakers and the removal and replacement of low rated circuit breakers with breakers having higher ratings by unauthorized personnel. The locking means of this invention, however, does not prevent the removal and replacement of low rated circuit breakers with replacement breakers having equally low ratings.

Referring now to FIGURE 3 in particular, each circuit breaker casing such as the circuit breaker 27 is provided with depressions 31 formed in the casing Walls on opposite sides of the breaker adjacent the lug 30. An aperture or opening 32 passes through the circuit breaker and connects the two depressions. A tab 35 is provided having a relatively small end 36 and a large end 37, the small end 36 containing an opening 38 and the large end an opening 39. Each depression 31 is proportioned so as to receive the small end 36 of the tab 35, the opening 38 being aligned with the aperture 32. By passing a fastening rod or member 40 through the aperture 32 and the openings 38 of the assembled tabs 35 and then riveting the ends of the member 40 to the tabs, the tabs 35 may be secured to the circuit breaker casing.

The apertures or slots provided in the flanges 12 and 13 on each side of the hook-shaped retaining elements 14 are positioned to receive the large ends 37 of the tabs 35 which extend downwardly from the circuit breaker casing. Therefore, a circuit breaker casing with tabs 35 may be mounted on the support plate 10 as best shown by FIGURE 2. When the breaker is in a fully mounted position on the support plate 10 in which the blade receiving socket of the breaker is in engagement with one of the contacts blades 16, the large ends 37 of the associated tabs 35 extend through the apertures 15 to the back surface of the support plate 10. As shown by FIGURE 2, the openings 39 in the large ends 37 of the tabs 35 are positioned so as to just clear the back surfaces of the flange 12 when the circuit breaker is fully mounted on the support plate 10.

With the circuit breakers having tabs 35 fully mounted on the panelboard as shown by FIGURE 2, a rod or strip locking member 45 may be passed through the tab openings 39 exposed below the back surfaces of the flange 12 as shown by FIGURE 3. The rod 45 is inserted axially from the end of the panelboard assembly. As long as the rod 45 is positioned through the openings 39, it effectively prevents the removal of the circuit breaker 27 from its plug-in engagement with the stationary contact 16. Since the openings 39 just clear the back surfaces of the flange 12, it can be seen that the rod 45 will contact the back surface of the flange and thus prevent the breaker 27 from being rotated any substantial distance around the retaining hook 14 to come out of engagement with the contact 16.

The bar 45 may be long enough to pass through the openings 39 of a plurality of tabs 35 secured to a plurality of circuit breakers mounted along the flange. By providing tabs 35 on all breakers having high ratings, it is possible to prevent the removal of all high rated breakers from the front of the support plate by unauthorized workmen. It may be desirable in practice, however, to allow ordinary workmen to remove and replace circuit breakers having low ratings. Therefore, circuit breakers having low ratings, 15 amperes for example, may be mounted without the tabs 35. Since the rod 45 does not engage in any way the breakers having low ratings, they may be removed and replaced at will.

In order to remove and replace high-rated breakers, or to install additional high-rated breakers, the support 10 is removed from the enclosure 9, and the rods 45 are withdrawn.

Thus, it can be seen that the invention provides locking means for effectively preventing the removal and replacement of selected circuit breakers by unauthorized personnel which does not interfere with the removal and replacement of other circuit breakers.

While only one embodiment of the invention has been shown, it will be readily apparent that various modifications thereof may be made, and it is intended to cover by the appended claims all such modifications as fall within the true spirit and scope of the invention.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. An electric circuit breaker panelboard comprising a support having front and back surfaces, a plurality of relatively stationary contacts mounted on the front surface of said support, a plurality of hook-shaped retaining elements each mounted on the front surface of said support in spaced relation to a respective one of said stationary contacts, a plurality of apertures in said support, respective ones of said apertures being spaced from respective ones of said stationary contacts and said retaining elements, a plurality of electric circuit breakers each having a generally rectangular insulating casing, a lug portion carried by each insulating casing at one end thereof, a plug-in type electrical connector carried by each casing adjacent the other end of the insulating casing, said mounting lug being adapted to coact with one of said retaining hooks to facilitate the pivotal movement of each circuit breaker about a retaining hook to move the plug-in type contact into plug-in electrical engagement with the respective one of said stationary contacts, at least one tab secured to each of selected ones of said circuit breakers, each of said tabs containing an opening, each tab extending through the respective aperture to the back surface of said support when the plug-in type contact of the associated circuit breaker is in plug-in electrical engagement with the respective stationary contact, and a rod passing through the opening in each of said tabs so as to interconnect said tabs and the back surface of said support to prevent the removal of the selected ones of said circuit breakers from said plug-in electrical engagement.

2. An electric circuit breaker panelboard comprising a generally rectangular enclosure having a back Wall and opposed side and end walls extending substantially perpendicular to said back wall, a support in said enclosure having front and :back surfaces and a plurality of apertures therein, a plurality of electric circuit breakers, means for mounting said circuit breakers on the front surface of said support, at least one tab secured to each of a plurality of said circuit breakers and extending through a respective one of said apertures to the back surface of said support when said circuit breakers are mounted on the front surface of said support, each of said tabs containing an opening, said openings of all of said tabs being in alignment when said circuit breakers are in mounted position, and a locking rod passing through said openings at the back surface of said support and preventing removal of said circuit breakers from said support, said locking rod being incapable of removal While said support is mounted in said enclosure, and said locking rod being removable to release said circuit breakers when said support is removed from said enclosure.

References Cited UNITED STATES PATENTS 2,916,675 12/ 1959 Middendorif 317-119 2,854,501 9/1958 Ludwig 317--99 2,579,168 12/1951 Ballou 317-120 3,173,063 3/1965 Kussy et al. 3 17120 ROBERT K. SCHAEFER, Primary Examiner. KATHLEEN CLAFFY, Examiner.

J. G. COBB, J. J. BOSCO, H. O. JONES,

Assistant Examiners. 

1. AN ELECTRIC CIRCUIT BREAKER PANELBOARD COMPRISING A SUPPORT HAVING FRONT AND BACK SURFACES, A PLURALITY OF RELATIVELY STATIONARY CONTACTS MOUNTED ON THE FRONT SURFACE OF SAID SUPPORT, A PLURALITY OF HOOK-SHAPED RETAINING ELEMENTS EACH MOUNTED ON THE FRONT SURFACE OF SAID SUPPORT IN SPACED RELATION TO A RESPECTIVE ONE OF SAID STATIONARY CONTACTS, A PLURALITY OF APERTURES IN SAID SUPPORT, RESPECTIVE ONES OF SAID APERTURES BEING SPACED FROM RESPECTIVE ONES OF SAID STATIONARY CONTACTS AND SAID RETAINING ELMENTS, A PLURALITY OF ELECTRIC CIRCUIT BREAKERS EACH HAVING A GENERALLY RETANGULAR INSULATING CASING, A LUG PORTION CARRIED BY EACH INSULATING CASING AT ONE END THEREOF, A PLUG-IN TYPE ELECTRICAL CONNECTOR CARRIED BY EACH CASING ADJACENT THE OTHER END OF THE INSULATING CASING, SAID MOUNTING LUG BEING ADAPTED TO COACT WITH ONE OF SAID RETAINING HOOKS TO FACILITATE THE PIVOTAL MOVEMENT OF EACH CIRCUIT BREAKER ABOUT A RETAINING HOOK TO MOVE 